JRE 6 update 22 sucrity issue

Hi
I have requirement to get macId using Applets. up to jre 6 update 21 it working properly. But in jre6 update 22 and latest versions by using loop back address or system name unble get mac address due to sucurity permissions. if I give manually all permissins jre6\lib\security\java.policy file then it is working fine. But client cannot do this about 30,000 machines as his requirement. SO please suggest me any other proggrammatic solution.
Thanks.